Fluorocarbon based fluids have found widespread use in industry in a number of applications, including as refrigerants, aerosol propellants, blowing agents, heat transfer media, gaseous dielectrics, and fire suppression.
However, certain compounds such as chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) are suspected of depleting atmospheric ozone and, thus, are harmful to the environment. Moreover, some of these compounds are believed to contribute to global warming. Accordingly, it is desirable to use fluorocarbon fluids having low or even zero ozone depletion potential, such as hydrofluorocarbons (HFCs), or those with a photolyzable carbon iodine bond, which exhibit short atmospheric lifetime when released at ground level. The use of single component fluids or azeotrope mixtures, which do not fractionate on boiling and evaporation, is also desirable.
Unfortunately, the identification of new, environmentally-safe, non-fractionating mixtures is complicated due to the fact that azeotrope formation is not readily predictable.
The industry is continually seeking new fluorocarbon-based mixtures that offer alternatives, and are considered environmentally safer substitutes for CFCs, HCFCs and HFCs in use today. Of particular interest are iodide containing compounds and other fluorinated compounds, which have low ozone depletion potentials and low global warming potentials. Such mixtures are the subject of this disclosure.
Although iodide containing compounds are of great potential interest, the purification of iodide containing compounds such as trifluoroiodomethane (CF3I) has presented challenges, and techniques for the removal of impurities from trifluoroiodomethane (CF3I) such as, for example, trifluoromethane (HFC-23), are in constant demand. Therefore, separation techniques such as azeotropic distillation, for example, would be highly desirable.
What is needed are compositions and techniques that may be used to prepare iodide containing compounds, such as trifluoroiodomethane (CF3I), of high purity.